Electromagnet with split core armature



July 18, 1950 J. F. o'BRlEN Erm. 27,515,258

ELECTROIIAGNET WITH SPLIT CORE ARHATURE Filed April 8, 1947 2Sheets-Sheet 1 H51 FIG. a /la A! /5 /ac /0 INVENTOR JOSEPH F. O'BRIEN BYJOHN BOAT DO ORNEY July 1.8, 1950 J. F. oBRlEN Erm. 2,515,258

ELECTROMAGNET WITHv SPLIT CORE ARMATURE Filed April 8, 1947 2Sheets-Shea?I 2 lNVENTOR JOSEPH F. O'BRIEN Y JOHN B. ATA LDO PatentedJuly 18, 1,950

ELECTROMAGN ET ARMA Lebanon, and John B. Cataldo, J., assignors to John-B. Pierce Joseph F. OBrien, Annandale, N.

WITH SPLIT CORE TURE Foundation, New York, N. Y., a corporation o! NewYork Application April B, 1947, Serial No. 74.0,144

6 Claims.

This invention relates to electrical relays and to solenoid mechanismscomponent thereto. It constitutes an improvement on the subject matterdisclosed and claimed in our similarly entitled copending applicationSerial No. 726,362 iiled February 4, 1947.

In that prior invention the relay and component solenoid 'mechanismspossess a single solenoid coil necessitating only a two-wire controlcircuit, as distinguished from earlier devices of similar type utilizinga pair of solenoid coils and a three-wire control circuit. Associatedwith the solenoid coil, as an armature, is a plunger assembly embodyinga plunger or throw rod which eiects the end result desired of thedevice. The action of the components of the plunger assembly undersuccessive momentary energizations of the solenoid coil, together withthe correlative action of mechanical latching means operative on theplunger assembly, makes it possible to achieve a throwing of the plungerrod and a holding of it in its thrown position, as in the closing andthe maintaining closed of a load circuit controlled by the relay,followed by a return thereof and a holding of it in its return position,and likewise for repeated operative cycles. Thus, such an electricalrelay can be effectively operated remotely by means of a singlemomentarily acting push-button in the control circuit.

'I'he present invention retains the generic combination of singlesolenoid coil. plunger assembly,

` and mechanical latching system, but eliminates certain disadvantagesinherent in the prior arrangement. f

Whereas in the prior arrangement resilient catches or latching elementsare employed to effect mechanical latching of certain of the plungerelements component to the plunger assembly. and these require closetolerances in the manufacture of various of the parts, as well asfrequent adjustment vduring use, 'in accordance with the presentinvention a system of rigid latches and levers, subject to neither ofthese disadvantages, is utilized to achieve the same end result.

Thus, itis an object of the present invention to eliminate both the needfor close tolerances in the manufacture oi' a device of the typeconcerned and the need for frequent adjustments during its use. V

It is an object to reduce the cost of manufacture and upkeep.

It is a further object to provide for more positive operation andgreater reliability.

These and additional objects and features of the invention will be fullyconsidered in the following detailed description of the preferredspecinc embodiment illustrated, by way of example only, in theaccompanying drawings.

In the drawings:

Fig. 1 is a vertical sectional on the line I-I, Fig. 2, but for the mostpart centrally through the device in its unenergized om or circuitopening, position;

Fig. 2 is a horizontal section taken on the line 2 2, Fig. 1;

Fig. 3 is a horizontal section taken on the line 3' 3| Fg- Fig. 4 is aview corresponding to that of Fig. l, but illustrating the device in itsenergized on, or circuit closing, position;

Fig. 5 is a section taken on the line 5-5, Fig. 4;

Fig. 6 is a view corresponding to those of Figs. 1 and 4, butillustrating the device in its unenergized on position;

Fig. 7 is a corresponding view,

but illustrating the device in its energized oli position;

Fig. 8 is a fragmentary perspective view oi a portion of the latchmechanism drawn to an enlarged scale, the position of the mechanismcorresponding to that of the upper part o! Fig. 6;

Fig. 9 is a similar view, the position corresponding to those oi'theupper parts of Figs. 4 and 7 and Fig. 10 is another similar view, theposition corresponding to that of the upper part of Fig. 1.

Referring to the drawings: In the form illustrated, which is nowconsidered to be the preferred form, the device comprises an externalcasing -III of cupped formation provided with an inset cover IIremovably secured in place by the screws I2. Both casing and cover arepreferably formed of a non-magneticA material such as almninum. Thecover is formed with an open neck portion Illa, into which is set aremovableterminal block I3 ot insulation, such block' carryingelectrical binding post arrangements I4 and I5. A set screw I6 serves tosecure terminal block I3 in place.

Within the casing I0 is disposed the solenoidoperated mechanism of theinvention, which, in this instance, serves to make and break anelectrical circuit, and therefore is operable as an electrical relay.Such mechanism includes a single solenoid coil I1 enclosed by a shell ofmagnetic material, advantageously steel. the shell comprising oppositepole pieces I8 and I9 of disc formation, and a coil encircling ring 20.A spacer ring 2 I, which is deslrably of electrical insulating fiber,serves to retain the solenoid coil and its enclosing shell snuglyagainst the internal view taken partially 3 shoulder formed bythe covermember .Electrical lead wires 22 and 23 extend from therespectivebindingpost arrangements I4 and |5 to the coil l1, and serveto conduct electricity thereto from a suitable control circuit (notshown), usually of low voltage-say 24 volts, which may be connected tothe device by means of the binding screws |4a and |5a. Wiring leads 24and 25 for connection with the electrical load circuit to be controlledby the device, a circuit which may be of considerably higher voltagethan the control circuit, say the usual 110 volts of an ordinarydomestic wiring system, pass through suitably provided openings in thecasing i8 to electrical union with respective contacts 28, 26 which aresecured in mutually spaced relationship to an insulating mount 28. .Theinterior of the casing below the mount 28 is preferably lined withinsulation 29.

As in my afore-referred-to copending application Serial No. 726,362, thesolenoid-operated mechanism includes, besides the single actuating coil,a plunger assembly which acts as an amature in the sense that certain ofits components are movable by the magnetic ux of the coil; suchmechanism includes, also, mechanical latching means operable on certaincomponents of the plunger assembly, and a. snap spring oper- :ale onother components of the plunger assem- The plunger assembly comprises aplunger throw-rod 38 of brass or other non-magnetic material to which isxed intermediate its length, a solenoid-responsive plungerv element 3|.The rod 30 is capped at one end by a striker element 32, here shown inthe shape of a disc, and is formed at the other end as an elongatedshank 38a on which are positioned an opposite or second striker element33, a snap spring in the form of a double equilibrium spring disc 34,and an electrical contact 35 sandwiched between blocks of insulation 38and 31. A conventional nut and washer serve to secure the several partstightly in place on the throw rod shank, as shown The spring disc 34 isanchored about its circumference in a frame structure 38 disposedbetween the mount 28 and the spacer ring 2|.

As so constituted the throw-rod extends through a suitably providedaperture inv the mount 28, so that electrical contact 35 is positionedto bridge the gap between the spaced contacts 28, 26 of the loadVcircuit when the rod is thrown by a given energization ofthe coil I1acting on the intermediate plunger element 3|, seeFis. 4.

The plunger assembly comprises, further, a

pair of solenoid-responsive auxiliary plunger elements 48 and 4| freelymounted on the throwrod 30 at opposite ends of the fixed intermediateplunger element 3|.

Secured to the opposite pole pieces I8 and I9 are respective bracketplates 42 and 43. These serve to mount the latching mechanism about tobe described. A coil spring 44 of brass spring wire or other suitable vnon-magnetic material is 'interposed between the two auxiliary plungerelements, and normally urges both outwardly against the respectiveplates as limit stops, see Pigs. 1 and 6. T-he spring disc 34, it shouldbe noted, determines the position of intermediate plunger element 3|relative to the auxlliary plunger elements, depending upon whichposition of equilibrium it is in, and energization of the'solenoid coill1 determines the particular position of equilibrium oi the spring disc.

The latching mechanism is arranged to be actuated by the oppositelypositioned striker elements 32 and 33, and to act upon the auxiliaryplunger elements by means of4 respective` latch arms which engageflanges 40a and 4 la of the respective auxiliary plunger elements. .Suchlatching mechanism comprises two independent and oppositely disposedidentical latch assemblies mounted on the bracket plates 42 and- 43,respectively.

Each latch assembly comprises a bell crank 50 pivoted on a horizontalaxis (considered from the standpoint of the drawing) for oscillationwithin a vertical plane in accordance with the control exerted by itscorresponding striker element 32 or 33, as the case may be. Asillustrated, the bell crank is pivoted to a bracket arm 42a or 43a,extending perpendicularly outwardly of the corresponding bracket plate42 or 43, its pivotal axis lying in a plane which is perpendicular tothe plane in which plunger rod 30 moves. A

`trip arm portion 50a of the bell crank extends into the path of travelof the corresponding striker element of rod 30, while a tripper armportion 50h extends through a suitably provided aperture of the bracketplate into the vicinity of the trip arm portion 5|a of a second bellcrank 5|, such second bell crank being pivoted to the bracket plate on avertical axis, that is to say so the pivotal axis is parallel to rod 30,for oscillation in a horizontal plane under the control of rst bellcrank 50 and having a latch arm portion 5|b which engages thecorresponding auxiliary plunger element 40 or 4|. The bracket arms 42a,and 43a are preferably struck from the bracket plates themselves,leaving the requisite apertures (desirably enlarged by suitable punch yoperation) for accommodating the tripper armv portions 50h of respectivebell cranks 50, see Figs. 2, 3, and 5, and Figs. 8, 9, and 10.

Associated with each bell crank 50 is a follower spring 52, constrainingthe trip arm portion 58a thereof to follow its striker element 32 or 33whenever the travel of such striker element is receding, and associatedwith each bell crank 5| is a follower biasing spring 53, Fig. 2,constraining the trip arm portion 5|a thereof to follow the recedingtripper arm portion 50h of the particular bell crank 50 concernedwhenever the trip arm portion 50a thereof is actuated by its strikerIelement on a positive stroke of the throw-rod 3l. The spring 52, itshould be noted, is stronger than the spring 53 for eilecting'theresults desired.

The unenerglzed ofP' position of the devicel is illustrated in Fig. l.There throw-rod 30 is maintained in its upwardly (from the standpoint ofthe drawing) thrown position by means of the spring disc 34, which is inits upward position of equilibrium, electrical contact 35 being in breakposition relative to its associated stationary load circuit contacts 26,28. The two auxiliary plunger l* elements 40 and 4| are maintained inoutward limit positions against the respective bracket plates 42 and 43by means of coil spring 44, the intermediate ilxed plunger element 3|being maintained substantially against the upper auxiliary plungerelement 40 and an air gap existing between such intermediate plungerelement and the lower auxiliary plunger element 4|. So far as thelatching mechanism is concerned, trip arm portion 50a of bell crank 55of the upper latch assembly is completely tripped by 'striker element32, thereby allowing latch arm 5|b of bell crank 50 of the same assemblytobe maintained in unlatching position relative to flange 40a of the 5upper auxiliary plunger element 4t by reason ot the iniluence of itsspring It, seev especially Pigs. 2 and 10. On the other hand, trip armportion a f the lower latch assembly-18 mailltained in untrlppedposition against its retracted striker element 38 by means of its springl2, thereby maintaining latch arm IIb of the same assembly in latchingposition overlying nange a oi' the lower auxiliary plunger element 4Iagainst the iniluence of its spring 53, see Fig. 3. (Fig. 8 alsoillustrates this condition, though inverted since it deals with theupper latch assembly.)

The energized -on position occurs when the push button or othercontrolinstrumentality of the control circuit (not shown) is actuated.thereby energizing the solenoid coil I1. This -oocurs only momentarily,but is sufllclent to throw the throw-arm 30 to eifective position, thepositions ofthe several parts being as illustrated in Fig. 4. Thecessation of actuation of the control instrumentality, as for instancethe release of the push button, de-energizes the solenoid coil, and theseveral parts assume the positions of Fig.

6.` Re-actuation produces the energized ol position of Fig. 7', whilecessation of such re-actuation returns the device to the unenergized olfposition of Fig. 1.

In the energized on position of Fig. 4, throwarm 30 has been throwndownwardly by action of energized solenoid coil I1, so that electricalcontact 35 makes with the stationary load circuit' contacts 26, 26.Spring disc 34, ilipped as it is to its opposite position ofequilibrium, is now in position to maintain throw-arm 30 downwardly, asthrown. Because of their mutual adjacency, auxiliary plunger element 40and intermediate plunger element 3| have been moved downwardly as aunit; auxiliary plunger element 4l has been restrained by latch arm 5Ibfrom movement upwardly under the influence of the magnetic flux of thesolenoid coil. By the time the throw-rod assumed its downward position,however, the trip arm portion 50a of the lower latch assembly wastripped by striker element 33, so that the latch arm portion 5|b thereofhas been moved to its non-latching position. Trip arm portion 50a of theupper latch assembly tried to completely follow the receding strikerelement 32 by reason of the urge of spring 52, but was stoppedmidwaybecause the latch arm portion Sib of the associated bell crank 5Istruck flange 40a of the downwardly displaced auxiliary plunger elementIl, as shown, and could not complete its full strike, see also Figs. 5and 9.

Upon de-energization of the solenoid coil the device assumes theunenergized on position of Fig. 6, wherein auxiliary plunger element 43has been displaced upwardly to its normal limit posivtion againstbracket plate 42 and the aforementioned latch arm portion 5th hassnapped into latching position under flange 40a thereof.

In both the energized on position of Fig. 4 and the unenergized onposition of Fig. 6 lthe lower latch assembly is unlatched; the latterposition is just the reverse 'of the unenergized "oil'" position of Fig.l.

The energized off position oi Fig. 7 is just the reverse of theenergized onf position of Fig. 4, the latch arm portion 5i b of thelower latch assembly, in this instance; having struck the ilange lla ofthe auxiliary plunger element 4I, thereby preventing the trip armportion Sla of the bell crank 50 from following the upwardly recedingstriker element 33, as illustrated.

Following this energized olT ergization of the solenoid coil il permitscoil spring M to return the device to the unenergized "oiT position ofFig. 1, whereupon the device is 5 in condition for repetition of theaforementioned operative cycle.

Whereas this invention is here illustrated and described with respect toa preferred speciilc construction thereof it should be understood thatvarious changes may be made therein and various other constructions maybe produced on the basis oi' the teachings hereof by those skilled inthe art, without departing from the generic scope of the invention asdeilned by the following claims.

l5 We claim:

l. In combination, a solenoid coil; a plunger,

arrangement mounted in said coil and operable thereby, said plungerarrangement comprising an elongated plunger rod, an intermediate plungerelement of magnetic material fixed to said rod, and respective auxiliaryplunger elements of magnetic material freely mounted on said rod atopposite ends of said intermediate plunger element for longitudinalmovementl along said rod; respective stops xed with respect to saidsolenoid coil limiting the extent of outward movement of said auxiliaryplunger elements relative to said intermediate plunger element;resilient means extending between said auxiliary plunger elementsnormally urging said elements against their respective stops; doubleequilibrium means ilxed with respect to said solenoid coil and withrespect to said plunger rod for maintaining said plunger rod in thealternate positions to which it is thrown by successive energizations ofsaid solenoid coil, said alternate positions placing the intermediateplunger element closely adjacent one or the other of the auxiliaryplunger elements and coincidentally producing a gap between it and theopposite auxiliary plunger element; oppositely disposed striker meansassociated with said plunger rod; and oppositely disposed latchassemblies pivoted respectively to said stops and engageablerespectively with said auxiliary plungers for alternating lockingagainst movement when the solenoid coil is energized the one of saidauxiliary plunger elements which is not adjacent said intermediateplunger element, each of said latch assemblies embodying a system oflevers having a trip arm extending into the path oi' movement of one otsaid striker means, and a latch arm responsive to the movement of saidtrip arm and operative to engage one of said auxiliary plunger elementsso as to restrain movement thereof.

2. The combination recited in claim l wherein each latch assemblycomprises a bell crank having a pivotal axis lying within a plane whichis substantially perpendicular to the plane within which the plunger rodmoves, a second bell crank w having a pivotal axis substantiallyparallel with said plunger rod, one arm of the first bell crank nproviding the trip arm which extends into the path of movement of astriker means, one arm of the second bell crank providing the latch arm65 which engages an auxiliary plunger element, and

the other arms of the said bell cranks being disposed relative to eachother to effect correlated movement of the two bell cranks in theoperation of the combination, a follower spring operative on the rstbell crank, and a follower spring operative on the second bell crank.

3. The combination recited in claim l wherein the respective stops arebracket plates mounted at opposite ends of the solenoid coil, theplunger rod l7| operatively extending through said bracket position,de-enplates. and wherein the respective latch assemblies are mounted onsaid bracket plates. l

4. The combination recited in claim 1, wherein the means for maintainingthe plunger rod in the alternate positions to which it is thrown bysuccessiveenergizations of the solenoid coil is a double equilibriumspring disc.

5. In an electrical relay having a solenoid coil and composite plungermeans, said means including a plurality of plungers of magnetic materialco-axially in line and movable one against the next, said meansbeing-operative as an armature,

. latch means operative on the plunger means,

comprising a pair of coacting bell cranks mounted for mutuallycorrelated movement, one oi.' said bell cranks having aresilientlypositione trip arm which is arranged to be tripped by a givenmovement of the plunger means, and the other latch arm normallymaintained in latching engagement with a component of said plunger.

means; tripping of the trip arm of one of said bell cranks eil'ectingunlatching of the latch arm of the other of said bell cranks. v

6. In a solenoid having a composite plunger, including a plurality ofplunger 'elements of magnetic material coaxially in line and movable oneagainst the next, 'as an armature, a latch operative to restrainmovement oi one element of the composite plunger, said latch comprisinga bell ,o

crank pivoted to engage and latch an -element of `oi" said bell crankshaving a resiliently biased `-said second bell crank having a trip armportion thereof extending` into the path of a second plunger element formovement thereby against the action of said'strong spring to releasesaid rst-named bell crank.

l JOSEPH F. O'BRIEN.

JOHN B. CATALDO.

REFERENCES CITED The following references are of record in the ille ofthis pmnt:

UNIIED STATES PATENTS Date Number Name 4 1,257,613 Kocourek Feb. 16,1918 1,449,212 Berry Mar. 20, 1923 v1,595,757 Coates Aug. 10. 19282,417,438 OBrien et al Mar. 18, 1947 FOREIGN PATENTS Number Country`Date v G reat Britain Dec. 27, 1933

